Hello Rhaegon5997,
Draver has shared an excellent tutorial, however, I can imagine, that for a non-programmer it may still be overwhelming. For that I can recommend a relatively new feature from github - github desktop. It is way easier to handle, and should be much easier for a non programmer.
1) You will need an account on github
2) Once you download the github desktop, it will propose to "clone a repository"
2.1) switch to "url", and enter the link from Draginol's github: https://github.com/Draginol/GC4_Localization
2.2) You can change local path to what ever you feel comfortable with
3) it will download all the files locally to your computer, and you will see a rather blank screen
But no worries! That's how you want it to be.
4) In the middle of the screen you can see the "show in explorer" button, click on it, and it will open all the files locally on your computer
5) Now you can edit game files, with any text editor (I recommend notepad++, but you can literally use text editor)
5.1) Take care about syntax. Do not delete brackets or similar. Change only words
6) After you change the file locally, it will automatically show up in github desktop, and even more, show you what the changes are:
Here you can see, that I edited the file "additionalStrings_1.xml" to have "I changed something here...". It also indicates lines of code where I have changed something, which makes it easier, if you see a mistake after proofreading.
7) After that, you can pretty much submit my clicking "commit to main" button at the left bottom in github desktop
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This may look like a long explanation, but will definitely be easier, than following a proper github guide on cloning repositories. As only skills required in my explanation are to able to create an account, download an app, and edit text.
And the best part, once you have set it up, you will only need to edit text from there on, without all the extra procedures.